This invention relates to an improved tape container closure.
In recent years containers have been hermetically sealed with easily opened tape closures which are affixed over a hole, or aperture, in the container wall by heat sealing or a pressure-sensitive adhesive; see U.S. Pat. No. 3,389,827. The closure has one free end which is easily gripped by fingers and pulled so as to separate it from the can. The contents, e.g. fruit juice, oil, salt, etc. can then be removed via the exposed aperture.
This closure provides a good, effective seal and has gained wide acceptance for sealing open cans. It is possible, however, to carefully break the seal, remove or adulterate the contents of the can, and then replace the tape closure, leaving no readily visible traces of the tampering.
A tape closure having a tamper indicator system which changes color when an attempt has been made to remove it with the aid of an organic solvents, is disclosed in U.S. Pat. No. 3,680,236. This indicator incorporates a layer containing a dye which dissolves and stains the backing when it is contacted with an organic solvent such as kerosene or toluene. Such an indicator will not function where the tape closure is removed by purely mechanical means.